pinhole against Nikkor 50mm f: 2 - 1964

[photoni]

I tried to change the name of the first post "sunset"
... it's not possible Andrea 48 hours seem short to me :)

 

I wanted to add these photos taken with greater accuracy
ISO 800
with tripod
lateral sun.

I used the Sony A7 fs, with my normal Nikkor-H 50 f: 2 lens (aperture 8 or 11) UP
(from 1964 without anti-reflective coating)
and others with pinhole ø 0.15 mm DOWN
it is not a pinhole - laser, but made with abrasion, used for microscopes
( blurred leaves moved by the wind)
unfortunately there are reflections, the filters are in front

 

 

- with BG39

 

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- BG39 + BG25 (Wet collodion emulation)

 

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- BG39 and torch filter similar to ZWB2
two notes, the leaves are green ... strange
WOW ... the UV transmission of the PinHole appears to be similar to the Nikkor-H

 

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- red 25A (~ 580nm)

 

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- red 25A (false color)

 

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- IR Kodak Wratten 87 in jelly 750nm

 

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- pinhole with unknown IR filter

 

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- pinhole without any filter

 

 

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- Nikkor-H with 2 unknown green filters, together

 

 

[dabateman]

That ZWB2,  isn't ZWB2. 

Too much green. Might be zb2.

What color is the filter? 

Cam you see through it with your eyes? 

[photoni]

8 hours ago, dabateman said:

That ZWB2,  isn't ZWB2. 

Too much green. Might be zb2.

What color is the filter? 

Cam you see through it with your eyes? 

 

is the glass of the: Alonefire X901UV 10W 365nm UV Flashlight

the information is: hard toughened black filter optical lens

it is a black filter, if I look at the sun (or a tungsten light) I only see a red / brown disc

in a similar flashlight it was referred to as ZWB2

[dabateman]

Ok so then I am totally confused.  If you can't see through the flashlight filter,  only the tinny IR leakage, than it maybe ZWB2. At 2mm thickness it should block everything from 410nm to 650nm. So where is the green coming from? 

Also 1mm BG39, if real BG39 is enough to block the IR from a Zwb2 or UG1 filter. Again how are you getting green.

The pinhole image at least has dark roof tops and trees so I can believe its UV.

[Andy Perrin]

None of the glasses are Schott, dabateman, so we can’t take it for granted that they have the Schott blocking etc. 

[Kai]

According to my observations, green in the UV image - if it was taken in sunlight - is always NIR leakage. In sunlight there is simply to little light with a wavelength below of 340 nm. And only that appears green (depending on the color mode in RAW development).
As a test, it is recommended to take an additional NIR blocker. I use one (or even two) QB21 for this.
(Canon EF 2.8-28 mm, Canon EOS 6 D-FS, sunlight (cloudless sky), WB PTFE)

 

 

 

See also:
https://www.ultravioletphotography.com/content/index.php?/topic/4892-low-cost-color-chart-for-uv-a/&do=findComment&comment=50160

[photoni]

1 hour ago, Kai said:

According to my observations, green in the UV image - if it was taken in sunlight - is always NIR leakage. In sunlight there is simply to little light with a wavelength below of 340 nm. And only that appears green (depending on the color mode in RAW development).
As a test, it is recommended to take an additional NIR blocker. I use one (or even two) QB21 for this.

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Kai, I think your guess is correct.
Thanks
But I wonder .... why do you use QB21 (= BG38) and not QB39 (= BG39) which blocks the red better? ... or S8612

 

 

7 hours ago, dabateman said:

The pinhole image at least has dark roof tops and trees so I can believe its UV.

If tomorrow it is sunny I will try to put the black filter ZWB2 behind pinhole, and in front a BG39 (China glass 1mm) and a BG18 (Jena glass 2mm)

[Kai]

1 hour ago, photoni said:

But I wonder .... why do you use QB21 (= BG38) and not QB39 (= BG39) which blocks the red better? ... or S8612

I haven't tried that many filters. According to the transmission curves shown by the provider, I liked the high UV permeability of the QB21. And the NIR suppression seemed sufficient for a ZWB2.

Unfortunately, I have no way of precisely measuring the filters myself ...

 

I'm looking forward to your picture results! 

[Andy Perrin]

S8612 is always the best. It is made only by Schott. People using Chinese glass will have to experiment with the IR blocking until the odd colors go away. The Chinese glass spectra have too much variation to rely on, so the best guide is experimenting. 
 

Also those graphs above are linear, so you cannot judge blocking from them. You need the diabatic or logarithmic graphs for that. 

[photoni]

On 10/26/2021 at 8:50 PM, Kai said:

According to my observations, green in the UV image - if it was taken in sunlight - is always NIR leakage.

 

I did other tests by putting the "ZWB2 type" filter behind the lens, the results confirm what Kai said.
only ZWB2 sees more IR than UV
ZWB2 + BG39 (1mm) sees a part of the visible green
ZWB2 + BG39 (1mm) + BG18 (2mm) see UV only
[the BG18 is a Jena Glass, similar BG39]

 

 

I did the pinhole test three times, but there are too many reflexes between the glasses, I have to find a solution.

 

 

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On 10/26/2021 at 2:47 PM, dabateman said:

Ok so then I am totally confused.

 

me too ... you can't make spaghetti with tomato sauce with Chinese rice noodles

[Andy Perrin]

Yep, the third image is true UV. I have to say, artistically that green leaf look on image 2 is striking! 
 

Long lens shade for the pinhole maybe?

[photoni]

On 10/27/2021 at 10:12 PM, Andy Perrin said:

Long lens shade for the pinhole maybe?

side light came in from the ring ": -S

 

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today sun

test with Sony A7 fs and Pinhole ø 0.15 - focal lenght approx ~ 50mm - aperture approx ~ f: 330 - ISO 1600

RAW developed with Capture One  - White balance on white house

 

In front I put a piece of transparent CD (without mirror layer)

 

What do the green - yellow - blue colors mean in the third photo

someone can translate the test for me?

 

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BG39 (china glass) very thin, i think 1mm thick

 

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BG39 (China Glass) + BG25 - 2mm thick (Jena Glass)

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BG39 + ZWB2 2mm thick (China Glass)

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BG39 + ZWB2 (China Glass) + BG18 (Jena Glass)

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....... and RED 25A ~580nm ... what a fake rainbow there is here ? ...

on the left, in the IR maybe there are the crossed curves of the bayer filter?

 

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[dabateman]

Your very first spectroscopy experiment.  How cool.

You see the faint dark bands in the bright over exposed spectrum.  Those are the fraunhofer lines. If you reduce your shutter speed to get a better non blown out exposure ,  you can use them to calibrate your wavelengths. 

https://en.m.wikipedia.org/wiki/Fraunhofer_lines#Sources

The green is deep uv the blue is not.

 

[photoni]

4 hours ago, dabateman said:

Your very first spectroscopy experiment.  How cool.

You see the faint dark bands in the bright over exposed spectrum.  Those are the fraunhofer lines. If you reduce your shutter speed to get a better non blown out exposure ,  you can use them to calibrate your wavelengths. 

https://en.m.wikipedia.org/wiki/Fraunhofer_lines#Sources

The green is deep uv the blue is not.

 

Thanks

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I tried again with the CD and the Nikkor-H 50mm @ ø f: 16 with different filters

later with photoshop I inserted the "Fraunhofer" scale, it seems to see up to 350nm.
Below I put the photo with all the files in proportion

... only now I understand that green is the extreme of the UV scale,
the pinhole sees, but this lens does not.

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the darker part under the standard yellow green mean that the BG39 does not block all visible light?

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This is with BG39 + ZWB2

 

 

[www.ultravioletphotography.com/content/index.php?/profile/376-kai/]

Kai how do you manage to take those pictures with the crisp fraunhofer lines ?

 

 

[dabateman]

Do you have two razor blades very close to each other to only allow a slit of light to the cd?

Most likely that will improve the quality of the lines.